Military, civilian and commercial entities have all recognized the need for precise positioning technology. The military seeks to be able to locate and track soldiers or vehicles as they progress across the battlefield. Civilian government entities want to locate fire fighters, for example, in burning buildings. The market for commercial navigation services using, for example, global positioning system (GPS) technology has grown significantly.
Traditional positioning technologies have suffered in high multi-path environments. Traditional approaches include, for example, GPS, and impulse ultrawideband signaling. GPS fails to provide accurate results in high multipath environments, and its low signal strength makes the signal vulnerable to jamming. Impulse ultrawideband technology suffers from the fact that it is fundamentally ultra-wideband and hence cannot be confined to previously unallocated bands of the spectrum (“spectrum”). Thus, it can only be used at relatively low power levels so as not to interfere with communications within bands of the spectrum allocated by the government for use by other services. Impulse ultrawideband signaling also suffers from long acquisition times and ease of interception.